L. MECHANICS AND ENGINEERING. 537 



saturated, explodes v/ith the violence of nitro - giycerine. 

 Apart, the elements are harmless, and the miner may pour the 

 proper proportion of each into a tube and place in position, 

 adding the fuse when it is prepared. Up to the time of mix- 

 ing he would be in no danger, and after that no more than 

 he is liable to in treating nitro-glycerine, gun-cotton, or gun- 

 powder. Sir Charles thinks Dr. Sprengel's methods are not 

 entirely practical at present, but that there is in them the 

 germ of an invention of very great value. 3 A^May 31, 

 1873,612. 



NEW METHOD OF lEON-MAKING. 



According to The English Mechanic ^2, new process of iron- 

 making, which dispenses with the blast furnace, has been 

 practically tested, and specimens of its produce shown at 

 Wolverhampton. The bloom is made direct from the ore, 

 which is ground, mixed with lime and pitch, and baked in a 

 coke oven. This is treated as pig-iron, and a furnace being 

 charged with it, it is ready for the helve or the squeezers in 

 half an hour. The inventors claim that by their process they 

 can make a ton of finished iron from the ore at an expenditure 

 of only two tons of coal ; that they can make German steel 

 as cheaply as cast iron, and that they can, furthermore, make 

 the latter equal in purity to charcoal iron. 18 A July 18, 

 1873, 452. 



ELECTRIC APPARATUS FOR INDICATING LEAKAGE IN SHIPS. 



Sortais has devised an electrical apparatus to be placed in 

 the hold of ships for the purpose of giving warning in case 

 of a leakage. On the entrance of the water a current is es- 

 tablished, and notice thus given to the officers. 15 A^May 

 31,1873,699. 



NEW MOTOR FOR SEWING-:MACHINES, ETC. 



A decidedly novel steam-engine is said to have been in- 

 vented by F. Siemens, of Dresden, which has neither cylinder, 

 piston, guide-rods, cranks, nor valves, but apparently only a 

 boiler, the interior arrangement of which for the present con- 

 stitutes the secret of the patentee. The steam remains, as well 

 as works, within it, not a drop of water being lost. It is only 

 adapted to produce one-tenth horse-power ; but it is always 



Z2 



